While the sedimentation of solutions or the like by centrifuging at low or normal temperatures meets with no difficulties whatever and has been known for a long time in mechanical chemistry, problems will occur when centrifuging is to be performed under the simultaneous influence of high temperatures. If high temperatures are required, the usual materials used in the centrifuge industry for the centrifuge rotor, such as aluminum or titanium alloys, often prove insufficient. Their disadvantage lies in the reduced strength which occurs with increasing temperature and, in addition, the chemical reactivity of these materials with the material mixtures to be separated increases as a rule with increasing temperature.
Due to the drop in strength caused by the action of the heat, the rotors, particularly of ultra-centrifuges, can no longer withstand the stresses occurring at accelerations of, say, more than 200,000 x g. Such and higher accelerations are required, however, to achieve satisfactory separation power or diffusion effect by centrifuging where molten systems are involved.
It has already been suggested to laminate a rotor and to construct it of layers of different materials (DT-OS 2,453,650), liquid plastics, for example, being cast into the rotating jacket consisting of a mechanically stronger layer, around which wire is possibly wound in addition. Besides increasing corrosion resistance and decreasing weight, this is intended to provide simple and low-cost production. But a rotor of this type is unsuited for a heated ultra-centrifuge because, among other factors, it can be subjected to only moderate thermal stresses without deforming due to plastification of its inner layers.
It is an object of the invention to provide a method by which the sedimentation, particularly also of high-melting metals and metal alloys, is possible by centrifuging the material mixtures.
It is also an object of the present invention to solve the problem of providing the sedimentation of particles proper to the metal, as well as the problem of the separation of impurities.
It is further an object of the present invention to provide a heatable rotor for ultra-centrifuges, permitting, at justifiable technical expense, an increase of the melting temperature up to 2000.degree. C and more in continuous operation.